The present invention relates to a shape-recoverable resin foamed product.
Heretofore, as a sealing material for filling a space, there have been known resin foamed products comprising shape-memory polymers which are heated at a time of application. (Japanese Patent Publications (KOKOKU) No. Hei 4-17980, (KOKOKU) No. Hei 7-39506, (KOKAI) No. Hei 6-298988, and (KOKAI) No. Hei 6-239955)
However, the above resin foamed products require time and labor for heating at a time of application, and also there may be some portions which can not be heated.
Also, there has been proposed re-expandable foamed plastic chips obtained by contracting a resin foamed product comprising a styrene-acrylonitrile based resin as a base resin and a specific volatile organic solvent as a foaming agent. [Japanese Patent Publication (KOKAI) No. Sho 62-13441]
However, since the chips contain the styrene-acrylonitrile resin as the base resin, the chips are liable to cause buckling at the time of contraction. To prevent the buckling, a high foaming magnification rate is required so that a cell diameter becomes large, and a characteristic, such as a heat insulating property, is decreased due to convection in the cell. Also, at a time of the re-expansion, spaces are created among chips so that the chips can not sufficiently fill the space. Further, since the chips re-expand, although the chips have a shape corresponding property to a certain extent, there has been a defect such that a desired shape design is difficult.
Accordingly, one object of the invention is to provide a shape-recoverable resin foamed product, which can substantially prevent defects of the prior art; has an excellent heat insulating property, fill property, sealing property and applicability; and can be advantageously used in a wide area as a heat insulating material for pipes; heat insulating material for buildings; buffer material for packages; cushion material for sport and leisure; sealing material for windstorm, dustproof, soundproof and waterproof in connecting portions of a civil engineering, construction and vehicle; and wood grain material.
Another object of the invention is to provide a shape-recoverable resin foamed product as state above, wherein the shape covering time can be controlled as desired.
A further object of the invention is to provide a shape-recoverable resin foamed product preferably used as not only a sealing material and a wood grain material but also a cushion material for packages, covering material, buffer material and heat insulating material.
A still further object of the invention is to provide a shape-recoverable foamed product and a laminated structure preferably used as a sealing material and wood grain material having an excellent handling property, filling property or applicability.
Further objects and advantages of the invention will be apparent from the following description of the invention.